text: Although generalizable, the limit is defined in the context of biomolecular X-ray crystallography, where a typical experiment consists of exposing a single frozen crystal of a macromolecule (generally protein, DNA or RNA) to an intense X-ray beam. The beams that are diffracted are then analyzed towards obtaining an atomically resolved model of the crystal. Such decay presents itself as a problem for crystallographers who require that the diffraction intensities decay as little as possible, to maximize the signal to noise ratio in order to determine accurate atomic models that describe the crystal.